Prior art machinery for vibration and pressure moulding exhibit an extraordinarily complicated design, with a multiplicity of hydraulic or pneumatic piston and cylinder assemblies both to achieve compaction pressure and to realise the desired vibration. Their mechanics are complicated and consequently give rise to unreliable operation with frequent down-time and subsequent repairs. The complex mechanical construction of these prior art devices also entails relatively high manufacturing costs. Neither do the prior art constructions allow for the use of any pressure medium other than hydraulic oil in cases where it is necessary to create high compaction pressure, greater than approx. 50 tons.